interface Session {
  id: string
  title: string
  model: string
  provider: string
  createdAt: number
  updatedAt: number
}

interface Message {
  id: string
  sessionId: string
  role: 'user' | 'assistant' | 'tool'
  content: MessageContent[]
  createdAt: number
}

// 保存消息（fire-and-forget）
window.electron.ipc.invoke('db:saveMessage', message)

// 加载会话历史
const messages = await window.electron.ipc.invoke('db:getMessages', sessionId)

interface ChatStore {
  sessions: Session[]
  activeSessionId: string | null
  messages: Record<string, Message[]>

  createSession(): Session
  deleteSession(id: string): void
  addMessage(sessionId: string, message: Message): void
  updateMessage(sessionId: string, messageId: string, updates: Partial<Message>): void
}